Golf club

ABSTRACT

There is provided a golf club including a head and a shaft detachably attached to the head, and having excellent reliability. This golf club includes a head, a shaft, a sleeve, and a screw. The sleeve is fixed to a tip part of the shaft. A head has a head body and an engaging member. The engaging member is fixed to the head body. Rotation of the sleeve to the head is regulated based on engagement between the sleeve and the engaging member. Withdrawal of the sleeve from the head is regulated based on connection between the sleeve and the screw. The screw is a multiple-thread screw.

TECHNICAL FIELD

The present invention relates to a golf club. In particular, the present invention relates to a golf club having a head and a shaft detachably mounted to each other.

BACKGROUND ART

A golf club having a head and a shaft detachably mounted to each other has been proposed. It is useful to detachably mount the shaft and the head body to each other for several reasons. If golfers themselves detachably mount the shaft and the head body to each other, the golfers can change the head and the shaft easily. For example, golfers who cannot satisfy the performance of the purchased golf club easily change the head and the shaft by themselves. The golfers themselves can easily assemble an original golf club in which a favorite head and a favorite shaft are combined. The golfers can purchase the favorite head and the favorite shaft, and can assemble the head and the shaft by themselves. Golf club stores can select a combination of a head and a shaft properly corresponding to the golfer, and sell the combination. The head and the shaft detachably mounted facilitate the custom-made golf club.

U.S. Patent Application Nos. 2009/0286618 and 2009/0286611 disclose a golf club having a head and a shaft detachably mounted to each other. These U.S. patent applications disclose a structure in which an axis of a shaft hole of a sleeve is inclined to a hosel axis. The structure can adjust a loft angle or the like.

A structure using a hosel insert 200 is disclosed in FIGS. 2 and 60 of U.S. Patent Application No. 2009/0286618. The hosel insert 200 is fixed to an inside of a hosel hole. The hosel insert 200 can prevent rotation of a sleeve.

Japanese Patent Application Laid-Open No. 2012-86010 discloses a golf club having an engaging member. The golf club includes a head, a shaft, a sleeve, and a screw. The sleeve is fixed to a tip part of the shaft. The head has a head body and an engaging member. The engaging member is fixed to the head body. Rotation of the sleeve to the head is regulated based on engagement between the sleeve and the engaging member. Withdrawal of the sleeve from the head is regulated based on connection between the sleeve and the screw. In the golf club, a connected state where the screw is connected to the sleeve and a disconnected state where the screw is removed from the sleeve can be mutually shifted. The head body has a screw part for connecting the engaging member. The engaging member has a screw part. The screw part of the head body is connected to the screw part of the engaging member.

CITATION LIST Patent Literature

Patent Literature 1: U.S. Patent Application Publication No. 2009/0286618

Patent Literature 2: U.S. Patent Application Publication No. 2009/0286611

Patent Literature 3: Japanese Patent Application Laid-Open No. 2012-86010

SUMMARY OF INVENTION Technical Problem

When the shaft (sleeve) is insufficiently fixed, a function as the golf club cannot be fulfilled. Certain fixation between the shaft and the head leads to the reliability of the club. Meanwhile, in respect of convenience, attaching/detaching work is preferably easy.

It is an object of the present invention to provide a golf club including a head and a shaft detachably attached to the head and having excellent reliability and convenience.

Solution to Problem

A golf club of the present invention includes: a head; a shaft; a sleeve; and a screw. The sleeve is fixed to a tip part of the shaft. The head has a head body and an engaging member. The engaging member is fixed to the head body. Rotation of the sleeve to the head is regulated based on engagement between the sleeve and the engaging member. The sleeve has a sleeve screw part. Withdrawal of the sleeve from the head is regulated based on connection between the sleeve screw part and the screw. A connected state where the screw is connected to the sleeve and a disconnected state where the screw is removed from the sleeve can be mutually shifted. The screw is a multiple-thread screw.

Preferably, the multiple-thread screw is a double-thread screw.

Preferably, the head body has a screw part A for connecting the engaging member. Preferably, the engaging member has a screw part B. Preferably, the screw part A is connected to the screw part B.

Preferably, the golf club further includes an intermediate member. Preferably, the intermediate member has a screw part which can be connected to the screw. Preferably, the screw part of the intermediate member is a multiple-thread screw.

Preferably, the screw has a first screw part, and a second screw part having an outer diameter greater than the first screw part. Preferably, the head body has a body screw part. Preferably, in the connected state, the first screw part is connected to the sleeve screw part. Preferably, in the connected state, the second screw part is connected to the body screw part. Preferably, the first screw part and the second screw part are multiple-thread screws. Preferably, the sleeve screw part and the body screw part are multiple-thread screws.

Preferably, the head body connected to the second screw part is elastically deformed by an axial force of the screw.

The head body may have a screw part for connecting the engaging member. The engaging member may have a screw part. The screw part of the head body may be connected to the screw part of the engaging member.

In the connected state, the engaging member may receive the axial force of the screw in the connected state.

The screw may be allowed to be screw-connected to the intermediate member in the disconnected state.

The screw may be configured so that it cannot be screw-connected to the intermediate member in the connected state. The screw may be configured so that it can be screw-connected to the intermediate member in the connected state.

The screw may be configured to be screw-connected to the intermediate member in a process in which the connected state is shifted to the disconnected state.

The intermediate member may be in a non-fixed state. Release of the intermediate member in the non-fixed state by gravity may be prevented. The intermediate member may be in a fixed state.

A space may exist, which can allow the intermediate member to move in an axial direction.

Preferably, the intermediate member may receive the axial force from the screw in the connected state.

Advantageous Effects of Invention

A golf club having excellent reliability and convenience can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing a golf club according to a first embodiment of the present invention;

FIG. 2 is an exploded view of FIG. 1;

FIG. 3 is a cross sectional view of FIG. 1, FIG. 3 is a cross sectional view of a vicinity of a hosel, and FIG. 3 shows a connected state;

FIG. 4 is an exploded view of FIG. 3, and FIG. 4 shows a disconnected state;

FIG. 5 shows a side view and a bottom view of a sleeve;

FIG. 6 is a perspective view of the sleeve of FIG. 5;

FIG. 7 is a cross sectional view taken along line F7-F7 of FIG. 5;

FIG. 8 is a cross sectional view taken along line F8-F8 of FIG. 5;

FIG. 9 shows a side view and a bottom view of an engaging member;

FIG. 10 shows a side view and a bottom view of a washer;

FIG. 11 shows a side view, a bottom view, and a cross sectional view of an intermediate member;

FIG. 12 shows a side view and a plan view of a screw according to the first embodiment;

FIG. 13 is a cross sectional view taken along line F13-F13 of FIG. 3;

FIG. 14 is a partially cutout perspective view of a head;

FIG. 15 is a cross sectional view of a golf club according to a second embodiment;

FIG. 16 is a side view showing an example of a double-thread screw;

FIG. 17 is a side view showing an example of a single-thread screw;

FIG. 18 is a cross sectional view of a golf club according to a third embodiment;

FIG. 19 shows a side view and a plan view of a screw according to a third embodiment;

FIG. 20 is a cross sectional view of a golf club according to a fourth embodiment;

FIG. 21 is a cross sectional view of a golf club according to a fifth embodiment; and

FIG. 22 is a cross sectional view of a golf club according to a sixth embodiment.

DESCRIPTION OF EMBODIMENTS

The present invention will be described below in detail based on preferred embodiments with reference to the drawings.

Unless otherwise described, “an axial direction” in the present application means an axial direction of a hosel hole, and “A radial direction” means a radial direction of the hosel hole.

FIG. 1 shows a golf club 2 according to one embodiment of the present invention. FIG. 1 shows only a vicinity of a head of the golf club 2. FIG. 2 is an exploded view of the golf club 2. FIG. 3 is a cross sectional view of the golf club 2. FIG. 3 is a cross sectional view taken along a center axis line of a sleeve 8.

The golf club 2 has a head 4, a shaft 6, a sleeve 8, and a screw 10. The sleeve 8 is fixed to a tip of the shaft 6. A grip (not shown) is mounted to a butt of the shaft 6. A shaft-sleeve assembly 12 is formed by the shaft 6 and the sleeve 8 fixed to each other.

The golf club 2 further has an intermediate member 14 and a washer 16. As described later, the intermediate member 14 is not fixed to a head body 18.

The head 4 has a head body 18 and an engaging member 20. The head body 18 has a hosel hole 22 into which the sleeve 8 is inserted, and a through hole 24 into which the screw 10 is inserted. The through hole 24 penetrates a bottom part of the hosel hole 22, and reaches a sole. The head body 18 has a hollow part.

As shown in FIG. 3, the head body 18 has a flange 25. The flange 25 is located below the sleeve 8 (sole side) in a connected state. An inner diameter of the flange 25 is greater than an outer diameter d2 of the washer 16.

A type of the head 4 is not restricted. The head 4 of the embodiment is a wood type golf club. The head 4 may be a utility type head, a hybrid type head, an iron type head, and a putter head or the like. The shaft 6 is not restricted. A generalized carbon shaft, and a steel shaft or the like can be used.

The screw 10 is a screw for fixing the shaft 6 (assembly 12). The screw 10 is a screw for fixing the shaft. The shaft-sleeve assembly 12 is fixed to the head 4 by fastening the screw 10. A state where the shaft-sleeve assembly 12 is fixed is also referred to as a connected state in the present application. The connected state is a state usable as a golf club. The shaft-sleeve assembly 12 is separated from the head 4 by loosening the screw 10. Thus, in the head 2, the head 4 and the shaft 6 are detachably attached to each other. In other words, the shaft 6 is detachably attached to the head 4. FIG. 4 is a cross sectional view showing a state where the shaft-sleeve assembly 12 is disconnected from the head 4. The state where the shaft-sleeve assembly 12 is separated from the head 4 is also referred to as a disconnected state in the present application.

FIG. 5 shows a side view and a bottom view of the sleeve 8. The side view is an upper view of FIG. 5, and the bottom view is a lower view of FIG. 5. FIG. 6 is a perspective view of the sleeve 8. FIG. 7 is a cross sectional view taken along line F7-F7 of FIG. 5. FIG. 8 is a cross sectional view taken along line F8-F8 of FIG. 5.

The sleeve 8 has an upper part 26, an intermediate part 28, and a lower part 30. A bump surface 29 exists on a boundary between the upper part 26 and the intermediate part 28. The sleeve 8 has a shaft hole 32 and a screw hole 34. The shaft hole 32 is located medially in the upper part 26 and the intermediate part 28. The shaft hole 32 is opened to one side (an upper side). The screw hole 34 is opened to other side (a lower side). The screw hole 34 is located medially in the lower part 30. The screw hole 34 is a sleeve screw part. The screw hole 34 is a double-thread screw.

The upper part 26 is exposed in the connected state. In the connected state, the bump surface 29 abuts on a hosel end face 36 of the head 4. As shown in FIG. 1, an outer diameter of a lower end of the upper part 26 is substantially equal to an outer diameter of the hosel end face 36. In the connected state, the upper part 26 exhibits an appearance like a ferrule. In the connected state, the intermediate part 28 and the lower part 30 are located medially in the hosel hole 22.

An external surface of the intermediate part 28 of the sleeve 8 has a circumferential surface 40 and a recessed surface 42. The recessed surface 42 is a groove. The recessed surface 42 extends along an axial direction of the sleeve 8. The recessed surface 42 extends over the entire longitudinal direction of the intermediate part 28.

In the connected state, the circumferential surface 40 is brought into contact with the hosel hole 22. The entire circumferential surface 40 is brought into contact with the hosel hole 22. The contact collateralizes the retention of the sleeve 8 caused by the hosel hole 22. On the other hand, in the connected state, the recessed surface 42 is not brought into contact with the hosel hole 22. The recessed surface 42 contributes to weight reduction of the sleeve 8.

An external surface of the lower part 30 of the sleeve 8 forms a rotation-preventing part 44. A section shape of the rotation-preventing part 44 is a non-circular form. The rotation-preventing part 44 has a plurality of protruding parts t1. The protruding parts t1 are outwardly projected in the radial direction. The protruding parts t1 are disposed at equal intervals in a circumferential direction. In the embodiment, the protruding parts t1 are disposed at every 30 degrees in the circumferential direction.

As shown in FIG. 8, an axis line h1 of the shaft hole 32 is inclined to an axis line z1 of the circumferential surface 40 of the sleeve 8. The inclination angle θ1 is a maximum value of an angle between the axis line h1 and the axis line z1. In the connected state, the axis line z1 is equal to an axis line e1 of the hosel hole 22. The axis line h1 of the shaft hole 32 is equal to an axis line s1 of the shaft 6.

FIG. 9 shows a side view and a bottom view of the engaging member 20. The engaging member 20 has a tubular shape as a whole. An external surface of the engaging member 20 has a screw part 48 and a non-screw part 50. The screw part 48 is a male screw. The non-screw part 50 is a circumferential surface. The entire external surface of the engaging member 20 may be a screw part. The screw part 48 may be a multiple-thread screw. The screw part 48 may be a double-thread screw. The screw part 48 is an example of the screw part B.

A section shape of an inner surface of the engaging member 20 is a non-circular form. The section shape of the inner surface of the engaging member 20 corresponds to that of an external surface of the rotation-preventing part 44 of the sleeve 8. A plurality of recess parts r1 is formed in the inner surface of the engaging member 20. A shape of the recess part r1 corresponds to that of the protruding part t1 described above. The recess parts r1 are formed at equal intervals in the circumferential direction. The recess parts r1 are formed at every 30 degrees in the circumferential direction.

The inner surface of the engaging member 20 forms a rotation-preventing part 51. The rotation-preventing part 51 is engaged with the rotation-preventing part 44 of the sleeve 8, to prevent rotation of the sleeve 8.

FIG. 10 shows a side view and a bottom view of the washer 16. The washer 16 is an annular member disconnected at one place in a circumferential direction. The washer 16 has a first end part 16 a and a second end part 16 b. The axial position of the first end part 16 a is different from the axial position of the second end part 16 b. The washer 16 is a spring washer (spring metal washer).

FIG. 11 shows a side view, a bottom view, and a cross sectional view of the intermediate member 14. The side view is an upper view of FIG. 11; the bottom view is a middle view of FIG. 11; and the cross sectional view is a lower view of FIG. 11. The intermediate member 14 is a circular member. An outer peripheral surface 54 of the intermediate member 14 is a circumferential surface. An inner peripheral surface 56 of the intermediate member 14 is a screw part. The inner peripheral surface 56 is a female screw. The female screw is a multiple-thread screw. That is, the inner peripheral surface 56 of the intermediate member 14 is a multiple-thread screw. The multiple-thread screw is a double-thread screw.

FIG. 12 shows a side view and a plan view of the screw 10. The screw 10 has a head part 58 and an axis part 60. The axis part 60 has a screw part 62 and a non-screw part 64. The non-screw part 64 is located on the head part 58 side from the screw part 62. The screw part 62 is a multiple-thread screw. The screw part 62 is a double-thread screw. The screw part 62 is a double-thread screw corresponding to the screw hole 34.

The head part 58 has a recess part 66 for a wrench. The screw 10 can be axially rotated by using the wrench (a dedicated wrench or the like) fitted into the recess part 66. The sleeve 8 can be detachably mounted by the axial rotation.

The retention of the sleeve 8 is achieved by screw connection. As shown in FIG. 3, the screw hole 34 of the sleeve 8 is screw-connected to the screw part 62 of the screw 10. The screw connection prevents the withdrawal of the sleeve 8. An axial force caused by the screw connection is balanced with a pressure between the hosel end face 36 and the bump surface 29. In order to collateralize the axial force, a clearance K1 exists between a tip of the screw 10 and a bottom face of the screw hole 34 in the connected state (see FIG. 3).

FIG. 13 is a cross sectional view taken along line F13-F13 of FIG. 3. As shown in FIG. 13, the rotation-preventing part 44 of the sleeve 8 is engaged with the rotation-preventing part 51 of the engaging member 20. The engagement prevents the rotation of the sleeve 8 to the engaging member 20.

The engaging member 20 is fixed to the head body 18.

The method for fixing the engaging member 20 is not restricted, and examples thereof include welding, bonding, fitting, screw connection, and a combination thereof. In the embodiment, the screw connection is employed as the method for fixing the engaging member 20. As shown in FIG. 4, a screw part 70 is formed in the hosel hole 22. The screw part 70 is a female screw. The screw part 70 is screw-connected to the screw part 48 of the engaging member 20. The screw part 70 may be a multiple-thread screw. The screw part 70 may be a double-thread screw. The screw part 70 is an example of the screw part A.

Slight failure is not allowed in the engagement between the engaging member 20 and the sleeve 8. The commodity value of the club is lost by slight wobbling. High accuracy is required for positioning the engaging member 20. Positioning accuracy of the engaging member 20 is improved by forming the screw part 70 in the hosel hole 22 and screw-connecting the screw part 48 of the engaging member 20 to the screw part 70. That is, the engaging member 20 has reduced position error in an axial direction and reduced direction error of an axis line.

Preferably, the screw connection between the screw part 70 of the hosel hole 22 and the screw part 48 of the engaging member 20 is fastened by a force applied to the head from a ball at hitting the ball. The configuration prevents looseness of the screw connection caused by hitting the ball.

Welding is employed to fix the engaging member 20, in addition to the screw connection. That is, the screw connection and the welding are used in combination. At least a part of a boundary surface between the engaging member 20 and the head body 18 is welded, which is not shown in the cross sectional views of FIGS. 3 and 4. The welding may include a screw connection portion, or may not include the portion. The combined use of the screw connection and the welding ensures the fixation of the engaging member 20. The combined use of the screw connection and the welding prevents the looseness of the screw connection. The combined use of the screw connection and the welding improves fixing strength of the engaging member 20 to the head body 18.

When the welding is employed, a kind of the welding is not restricted. Examples of the kind of the welding include laser welding, arc welding, gas welding, and thermite welding.

In the embodiment, the engaging member 20 is welded to the head body 18 by heating from a hosel external surface 72. The method is suitable for welding the engaging member 20 located in a depth of the hosel hole 22. In the embodiment, the laser welding is employed. In the embodiment, the hosel external surface 72 is irradiated with laser, to weld the engaging member 20 to the head body 18. Since a heating range of the laser welding is local, the laser welding can suppress deformation of the engaging member 20 and the hosel hole 22. Therefore, high dimensional accuracy of the engaging member 20 and the hosel hole 22 tends to be maintained, and positional accuracy of the engaging member 20 tends to be also maintained.

Even if a heating trace is left in the hosel external surface 72 located in the head, the heating trace is invisible in the completed head. Therefore, it is unnecessary to restore the heating trace in order to improve an appearance of the head. The unnecessary restoration can improve productivity of the head.

FIG. 14 is a perspective view of the head 4 having a partially cutout face. As shown in FIG. 14, the hosel external surface 72 located in the head is irradiated with laser, to weld the engaging member 20 to the head body 18. Although the head body 18 includes a plurality of members; the engaging member 20 is welded to the head body 18 before all of the plurality of members is joined.

Slight failure is not allowed in the engagement between the engaging member 20 and the sleeve 8. The engaging member 20 is a separate body from the head body 18, to improve a freedom degree of a processing method of the engaging member 20. Thereby, the engaging member 20 can be processed with high dimensional accuracy. Therefore, accuracy of the engagement between the engaging member 20 and the sleeve 8 is improved.

As described above, the engaging member 20 is a separate body from the head body 18, and thereby the dimensional accuracy of the engaging member 20 is high. Therefore, a lower surface 74 (see FIG. 4) of the engaging member 20 tends to become perpendicular to the axial direction with high accuracy. The high orientation accuracy of the lower surface 74 tends to cause uniform dispersion of the axial force in the connected state in a circumferential direction of the engaging member 20. The uniform dispersion can improve the fixing strength of the engaging member 20.

In the connected state, the engaging member 20 receives the axial force from the screw 10. As shown in FIG. 3, the axial force caused by the screw 10 is transmitted to the engaging member 20 via the intermediate member 14. The engaging member 20 receives the axial force from the screw 10. The securely fixed engaging member 20 can withstand the axial force from the screw 10.

The intermediate member 14 is a separate body from the head body 18, to improve a freedom degree of a processing method of the intermediate member 14. Thereby, the intermediate member 14 can be processed with high dimensional accuracy. A position and posture of the intermediate member 14 in the connected state are stabilized with high accuracy by a combination of the highly accurate engaging member 20 and the highly accurate intermediate member 14. Therefore, in the connected state, a lower surface 80 (see FIG. 3) of the intermediate member 14 tends to become perpendicular to the axial direction with high accuracy. The high orientation accuracy of the lower surface 80 tends to cause uniform dispersion of the axial force in the connected state in the circumferential direction of the engaging member 20. The uniform dispersion can improve the fixing strength of the engaging member 20.

As described above, the intermediate member 14 is a separate body from the head body 18, to improve the freedom degree of the processing method of the intermediate member 14. Thereby, a screw part formed in the inner peripheral surface 56 of the intermediate member 14 is processed and formed with good accuracy. The screw hole 56 having good accuracy facilitates engagement between the screw hole 56 and the screw 10.

As described above, FIG. 4 shows a state where the head 4 is disconnected from the shaft-sleeve assembly 12 (hereinafter, referred to as a disconnected state). In the disconnected state, the screw 10 is not released from the head 4. The release prevention is achieved by the intermediate member 14.

As shown in FIG. 3, in the connected state, the intermediate member 14 is not screw-connected to the screw 10. In the connected state, the non-screw part 64 of the screw 10 is located medially in the intermediate member 14. An outer diameter of the non-screw part 64 is less than an inner diameter d7 (see FIG. 11) of the inner peripheral surface 56 of the intermediate member 14. The inner diameter d7 is measured on the basis of a tip of a screw thread. In the connected state, the intermediate member 14 does not affect screw connection between the screw 10 and the sleeve 8. The intermediate member 14 does not hinder the screw connection between the screw 10 and the sleeve 8.

On the other hand, as shown in FIG. 4, in the disconnected state, the intermediate member 14 is screw-connected to the screw 10. That is, in the disconnected state, the screw 10 is allowed to be screw-connected to the intermediate member 14.

In a golf club 400 to be described later, in the connected state, the intermediate member 14 is screw-connected to a screw 206. The intermediate member 14 has various functions.

In a process in which the screw connection between the sleeve 8 and the screw 10 is loosened, the screw part of the intermediate member 14 can be screw-connected to the screw part 62 of the screw 10. In the process in which the screw connection between the sleeve 8 and the screw 10 is loosened, screw connection between the screw part of the intermediate member 14 and the screw part 62 is naturally (automatically) caused. The screw connection between the intermediate member 14 and the screw 10 can be also maintained in a state where the screw 10 is completely removed from the sleeve 8 (see FIG. 4). Therefore, the release of the screw 10 is prevented.

Thus, in the golf club 2, the screw 10 cannot be screw-connected to the intermediate member 14 in the connected state. Furthermore, in the golf club 2, the screw 10 is screw-connected to the intermediate member 14 in a process in which the connected state is shifted to the disconnected state.

As shown in FIG. 4, an outer diameter d1 of the intermediate member 14 is greater than an inner diameter of the flange 25. That is, the intermediate member 14 has an outside dimension in which the intermediate member 14 cannot pass through an inner side of the flange 25. Therefore, the screw 10 screw-connected to the intermediate member 14 is not released.

The outer diameter d1 of the intermediate member 14 is greater than an inner diameter d4 (see FIG. 9) defined by a bottom face of the recess part r1 of the engaging member 20.

An axial directional length between a lower end face of the engaging member 20 and an upper end face of the flange 25 is represented by reference character Din FIG. 4. The length D is greater than a thickness C of the intermediate member 14. Therefore, a clearance exists between the lower end face of the engaging member 20 and the upper end face of the flange 25. An axial directional width K2 of the clearance is a difference (D−C).

In the connected state, the axial force caused by the screw 10 presses the intermediate member 14 against the lower end face of the engaging member 20 (see FIG. 3). On the other hand, in the disconnected state, the intermediate member 14 can abut on the upper end face of the flange 25 due to gravity (see FIG. 4).

The intermediate member 14 is not fixed to the head body 18. The intermediate member 14 is in a non-fixed state. The intermediate member 14 can move in the axial direction between the engaging member 20 and the flange 25.

The intermediate member 14 of the non-fixed state (free) tends to absorb dimension error. The intermediate member 14 in the non-fixed state facilitates engagement between the screws when the connected state is shifted to the disconnected state. The intermediate member 14 in the non-fixed state facilitates screw connection between the screw 10 and the intermediate member 14. In respect of a freedom degree of movement of the intermediate member 14, the difference (D−C) is preferably equal to or greater than 0.2 mm, more preferably equal to or greater than 0.3 mm, and still more preferably 0.5 mm. In respect of shortening the hosel hole 22 to reduce a weight of a hosel part, the difference (D−C) is preferably equal to or less than 1.0 mm and more preferably equal to or less than 0.8 mm.

When the intermediate member 14 can move in the radial direction, the absorbability of the dimension error is improved, and thereby the screws tend to be engaged. In this respect, a space may exist, the space can allow the intermediate member 14 to move in the radial direction. That is, in respect of the intermediate member 14 capable of moving in the radial direction, the outer diameter d1 of the intermediate member 14 may be less than an inner diameter d5 (see FIG. 4) of the hosel hole 22 in a position where the intermediate member 14 can exist. In respect of improving the freedom degree of movement of the intermediate member 14, a difference (d5−d1) is preferably equal to or greater than 0.1 mm, more preferably equal to or greater than 0.2 mm, and still more preferably equal to or greater than 0.3 mm. When the difference (d5−d1) is excessive, the intermediate member 14 moves excessively, which indeed may deteriorate the engagement between the screws. In this respect, the difference (d5−d1) is preferably equal to or less than 1.5 mm and more preferably equal to or less than 1.0 mm. In FIGS. 3 and 4, the inner diameter d5 and the outer diameter d1 are drawn so that the inner diameter d5 is identical to the outer diameter d1.

The axial force does not act on the flange 25 in the connected state. The flange 25 functions as a projecting part for preventing release. That is, the head body has an anti-dropping projection part to prevent dropping of the intermediate member 14. A shape of the projecting part for preventing release is not restricted. The projecting part for preventing release is disposed on a lower side (a sole side) of the intermediate member 14.

An axial directional length of the screw part 48 formed in the engaging member 20 is represented by reference character A in FIG. 9. In respect of a positioning effect of the engaging member 20 and fixing strength of the engaging member 20, the length A is preferably equal to or greater than 1.5 mm, more preferably equal to or greater than 2 mm, and still more preferably equal to or greater than 3 mm. In respect of suppressing cost of a step for processing the screw part 48, the length A is preferably equal to or less than 5 mm, more preferably equal to or less than 4.5 mm, and still more preferably equal to or less than 4 mm.

An axial directional length of the engaging member 20 is represented by reference character B in FIG. 9. In respect of widening a contact area of the engaging member 20 and the sleeve 8 to improve a rotation preventing effect, the length B is preferably equal to or greater than 5 mm, more preferably equal to or greater than 6 mm, and still more preferably equal to or greater than 7 mm. In respect of reducing a weight of the engaging member 20 to improve a design freedom degree of a position of a center of gravity of the head 4, the length B is preferably equal to or less than 12 mm, more preferably equal to or less than 11 mm, and still more preferably equal to or less than 10 mm.

A thickness of the intermediate member 14 is represented by reference character C in FIG. 11. In respect of suppressing deformation caused by the axial force, the thickness C is preferably equal to or greater than 0.8 mm, more preferably equal to or greater than 1 mm, and still more preferably equal to or greater than 1.2 mm. In respect of reducing a weight of the intermediate member 14 to improve a design freedom degree of a position of a center of gravity of the head 4, the thickness C is preferably equal to or less than 1.8 mm, more preferably equal to or less than 1.6 mm, and still more preferably equal to or less than 1.4 mm.

A maximum diameter of a screw head part 58 is represented by reference character d6 in FIG. 12. In respect of ensuring transmission of the axial force to the engaging member 20, the maximum diameter d6 is preferably less than the inner diameter of the flange 25. In other words, it is preferable that the screw 10 can pass through the inner side of the flange 25.

In respect of preventing deformation of the intermediate member 14, a difference (d4−d2) between the inner diameter d4 (see FIG. 9) of the engaging member 20 and the outer diameter d2 (see FIG. 10) of the washer 16 is preferably equal to or less than 0.5 mm, more preferably equal to or less than 0.3 mm, and still more preferably equal to or less than 0.1 mm. The difference (d4−d2) may be 0 mm or a minus value.

A material of the head body is not restricted. Preferable examples of the material include a metal, carbon fiber reinforced plastic (CFRP) and a combination thereof. More preferable examples include the metal. Examples of the metal include a titanium alloy, stainless steel, an aluminium alloy, a magnesium alloy, and a combination thereof. A manufacturing method of each of the members constituting the head body is not restricted. Examples of the manufacturing method include forging, casting, pressing, NC processing, and a combination thereof.

A material of the shaft is not restricted. Examples of the material of the shaft include carbon fiber reinforced plastic (CFRP) and a metal. A so-called carbon shaft and steel shaft can be suitably used. A structure of the shaft is not restricted.

A material of the sleeve is not restricted. Preferable examples of the material include a titanium alloy, stainless steel, an aluminium alloy, a magnesium alloy, and a resin. In respect of strength and lightweight, for example, the aluminium alloy and the titanium alloy are more suitable. It is preferable that the resin has excellent mechanical strength. For example, the resin is preferably a resin referred to as an engineering plastic or a super-engineering plastic.

A material of the engaging member is not restricted. Preferable examples of the material include a titanium alloy, stainless steel, an aluminium alloy, a magnesium alloy, and a resin. It is preferable that the resin has excellent mechanical strength. For example, the resin is preferably a resin referred to as an engineering plastic or a super-engineering plastic.

A material of the screw is not restricted. Preferable examples of the material include a titanium alloy, stainless steel, an aluminium alloy, a magnesium alloy, an engineering plastic, and a super-engineering plastic.

FIG. 15 is a cross sectional view of a golf club 100 according to a second embodiment. The golf club 100 has a head 104, a shaft 6, a sleeve 8, a screw 10, and a washer 16. The sleeve 8 is fixed to a tip of the shaft 6. A grip (not shown) is attached to a butt of the shaft 6. A shaft-sleeve assembly 12 is formed by the shaft 6 and the sleeve 8 fixed to each other.

Unlike the above-mentioned golf club 2, the golf club 100 does not have an intermediate member. As shown in FIG. 15, a head body 106 of the head 104 has a flange 108 in place of the intermediate member. A screw hole 110 is formed in an inner peripheral surface of the flange 108. The screw hole 110 is a female screw. The screw hole 110 is a body screw part. The screw hole 110 is a multiple-thread screw. The screw hole 110 is a double-thread screw. A specification of the screw hole 110 is the same as a specification of the screw part of the inner peripheral surface 56 of the intermediate member 14. A pitch Pt of the screw hole 110 is the same as a pitch Pt of the screw hole 56. A lead Ld of the screw hole 110 is the same as a lead Ld of the screw hole 56. The golf club 100 is the same as the golf club 2 except that the intermediate member 14 is integrated with the head body.

In a process in which the sleeve 8 is screwed, a screw part 62 is screw-connected to the screw hole 110. Furthermore, when the screw 10 advances to a connected state, the screw part 62 is screw-connected to the screw hole 110 and a screw hole 34. Furthermore, when the screw 10 advances to the connected state, screw connection between the screw hole 110 and the screw part 62 is released, and a screw connected portion of the screw hole 34 with the screw part 62 is increased. Finally, in the connected state, the screw connection between the screw hole 110 and the screw part 62 is released, and the screw hole 34 is screw-connected to the screw part 62 (see FIG. 15). The specification of the screw hole 110 is the same as a specification of the screw hole 34. The pitch Pt of the screw hole 110 is the same as a pitch Pt of the screw hole 34. The lead Ld of the screw hole 110 is the same as a lead Ld of the screw hole 34.

FIG. 16 is a side view showing an example of a double-thread screw. FIG. 17 is a side view showing an example of a single-thread screw. A usual screw is a single-thread screw. As shown in FIG. 17, in the single-thread screw, a pitch Pt is equal to a lead Ld. Meanwhile, as shown in FIG. 16, in the double-thread screw, a lead Ld is equal to twice of a pitch Pt. In the multiple-thread screw, a lead Ld is equal to an integral multiple of 2 or more of a pitch Pt. The single-thread screw, the double-thread screw, and the multiple-thread screw are specified in JIS B 0101:1994.

Examples of the multiple-thread screw include a triple-thread screw and a four-thread screw. In the triple-thread screw, a lead Ld is equal to 3 times of a pitch Pt. In the four-thread screw, a lead Ld is equal to 4 times of a pitch Pt.

In light of the balance between swiftness of tightening and difficulty of looseness, the double-thread screw and the triple-thread screw are preferable, and the double-thread screw is more preferable.

The pitch Pt is a distance between threads adjacent to each other. The pitch Pt is measured in the axial direction of the screw. The pitch Pt is specified in JIS B 0101:1994.

The lead Ld is a distance in which the screw advances in one turn. The distance is measured in the axial direction of the screw. The lead Ld is specified in JIS B 0101:1994.

The advance distance of the multiple-thread screw per one turn is greater than the advance distance of the single-thread screw. Therefore, the multiple-thread screw can shorten a time required for fastening the screw connection. Similarly, the multiple-thread screw can shorten a time required for releasing the screw connection.

The multiple-thread screw can shorten a time required for attaching and detaching the shaft. When the shaft-sleeve assembly 12 is attached to the head 4 in the embodiment, the screw part 62 of the screw 10 is fastened to the screw hole 34 of the sleeve 8. Since the screw part 62 and the screw hole 34 are the double-thread screws, a time required for the screw connection can be shortened. Therefore, the time required for attaching and detaching the shaft 6 can be shortened.

Furthermore, the inner peripheral surface 56 (female screw) of the intermediate member 14 is the double-thread screw in the first embodiment. Therefore, the time required for attaching and detaching the shaft 6 can be further shortened.

FIG. 18 is a cross sectional view of a golf club 200 according to a third embodiment. The golf club 200 has a head 204, a shaft 6, a sleeve 8, a screw 206, and a washer 208. The washer 208 is a spring washer. The sleeve 8 is fixed to a tip of the shaft 6. A grip (not shown) is attached to a butt of the shaft 6. A shaft-sleeve assembly 12 is formed by the shaft 6 and the sleeve 8 fixed to each other.

Unlike the above-mentioned golf club 2, the golf club 100 does not have an intermediate member. As shown in FIG. 18, a head body 210 of the head 204 has a flange 212 in place of the intermediate member. A screw hole 214 is formed in the inner peripheral surface of the flange 212. The screw hole 214 is a female screw. The screw hole 214 is a body screw part. The screw hole 214 is a multiple-thread screw. The screw hole 214 is a double-thread screw. A specification of the screw hole 214 is the same as a specification of the screw part of the inner peripheral surface 56 of the intermediate member 14. The head body 210 is the same as the head body 106 of the above-mentioned second embodiment.

FIG. 19 shows a side view and a plan view of the screw 206. The screw 206 has a head part 220 and an axial part 222. The axial part 222 has a first screw part 224, a second screw part 226, a first non-screw part 228, and a second non-screw part 230. The first screw part 224 is a male screw. The second screw part 226 is a male screw. The first non-screw part 228 is located between the first screw part 224 and the second screw part 226. The second screw part 226 is located on a head part 220 side with respect to the first screw part 224. The second non-screw part 230 is located between the head part 220 and the second screw part 226.

The second non-screw part 230 is useful to shorten a time required for fastening and removing the screw 206. The second non-screw part 230 contributes to weight saving of the screw 206.

The first screw part 224 is a multiple-thread screw. The first screw part 224 is a double-thread screw. The first screw part 224 is a double-thread screw corresponding to the screw hole 34 of the sleeve 8.

The second screw part 226 is a multiple-thread screw. The second screw part 226 is a double-thread screw. The second screw part 226 is a double-thread screw corresponding to the screw hole 214 of the flange 212.

The outer diameter of the second screw part 226 is greater than the outer diameter of the first screw part 224. The outer diameter of the male screw is a diameter of a virtual cylinder brought into contact with a top of the ridge of the male screw.

The diameter of a valley of the second screw part 226 is greater than the diameter of a valley of the first screw part 224. The diameter of a valley of the male screw is a diameter of a virtual cylinder brought into contact with the bottom of the valley of the male screw.

A pitch Pt of the second screw part 226 is the same as a pitch Pt of the first screw part 224. A lead Ld of the second screw part 226 is the same as a lead Ld of the first screw part 224.

The head part 220 has a recess 66 for a wrench. The screw 206 can be axially rotated by using the wrench (a dedicated wrench or the like) fitted into the recess 66. The sleeve 8 can be attached and detached by the axial rotation.

The retention of the sleeve 8 is achieved by two screw connections. As shown in FIG. 18, the screw hole 34 of the sleeve 8 is screw-connected to the first screw part 224 of the screw 206. The screw connection prevents the withdrawal of the sleeve 8. Furthermore, the screw hole 214 of the head body 210 is screw-connected to the second screw part 226 of the screw 206. The screw connection prevents the withdrawal of the sleeve 8.

The inner diameter of the screw hole 214 is greater than the inner diameter of the screw hole 34. The inner diameter of the female screw is a diameter of a virtual cylinder brought into contact with the top of the ridge of the female screw.

The diameter of a valley of the screw hole 214 is greater than the diameter of a valley of the screw hole 34. The diameter of the valley of the female screw is a diameter of a virtual cylinder brought into contact with the bottom of the valley of the female screw.

When the assembly 12 is attached in the golf club 200, the first screw part 224 of the screw 206 passes through the screw hole 214, and is screwed into the screw hole 34. Furthermore, the screw 206 advances to the connected state, screw connection between the screw hole 214 and the second screw part 226 is started. Furthermore, when the screw 206 advances to the connected state, a screw connected portion of the first screw part 224 with the screw hole 34 is increased, and a screw connected portion of the screw hole 214 with the second screw part 226 is also increased. Finally, in the connected state, screw connection between the first screw part 224 and the screw hole 34 is achieved, and screw connection between the second screw part 226 and the screw hole 214 is achieved (see FIG. 18).

FIG. 20 is a cross sectional view of a golf club 300 according to a fourth embodiment. The golf club 300 has a head 304, a shaft 6, a sleeve 8, a screw 206, and a washer 208. The head 304 has a head body 306. The washer 208 is a spring washer. The sleeve 8 is fixed to a tip of the shaft 6. A grip (not shown) is attached to a butt of the shaft 6. A shaft-sleeve assembly 12 is formed by the shaft 6 and the sleeve 8 fixed to each other.

A screw used for the golf club 300 is the screw 206 as in the above-mentioned golf club 200.

In the above-mentioned golf club 200, the engaging member 20 is a separate body from the head body 210. Meanwhile, in the golf club 300, a portion corresponding to the engaging member 20 is provided in the head body 306. That is, in the golf club 300, the portion corresponding to the engaging member 20 is integrated with the head body 306. Except for this point, the golf club 300 is the same as the above-mentioned golf club 200.

FIG. 21 is a cross sectional view of a golf club 400 according to a fifth embodiment. The golf club 400 has a head 404, a shaft 6, a sleeve 8, an intermediate member 14, a screw 206, and a washer 208. The washer 208 is a spring washer. The sleeve 8 is fixed to a tip of the shaft 6. A grip (not shown) is attached to a butt of the shaft 6. A shaft-sleeve assembly 12 is formed by the shaft 6 and the sleeve 8 fixed to each other. The head 404 has a head body 406 and an engaging member 20.

A screw used for the golf club 400 is the screw 206 as in the above-mentioned golf club 200 and golf club 300.

An intermediate member used for the golf club 400 is the intermediate member 14 as in the above-mentioned golf club 2.

An engaging member used for the golf club 400 is the engaging member 20 as in the above-mentioned golf club 2.

There are two differences between the golf club 400 and the above-mentioned golf club 2. The first difference is whether the intermediate member 14 is fixed. The second difference is a difference of screws.

Regarding the first difference, in the golf club 2, the intermediate member 14 is not fixed. Meanwhile, in the golf club 400, the intermediate member 14 is fixed. The intermediate member 14 is fixed as being sandwiched between the head body 406 and the engaging member 20. In the golf club 400, the above-mentioned axial directional width K2 (see FIG. 4) is zero. A method for fixing the engaging member 20 is the same as the method in the above-mentioned golf club 2.

Regarding the second difference, while the screw used for the golf club 2 is the screw 10, the screw used for the golf club 400 is the screw 206. As shown in FIG. 21, in the connected state, the screw connection between a first screw part 224 and a screw hole 34 is achieved, and screw connection between a second screw part 226 and a screw hole 56 is achieved.

FIG. 22 is a cross sectional view of a golf club 500 according to a sixth embodiment. The golf club 500 has a head 504, a shaft 6, a sleeve 8, an intermediate member 14, a screw 506, and a washer 508. The washer 508 is a spring washer. The sleeve 8 is fixed to a tip of the shaft 6. A grip (not shown) is attached to a butt of the shaft 6. A shaft-sleeve assembly 12 is formed by the shaft 6 and the sleeve 8 fixed to each other. The head 504 has a head body 509 and an engaging member 20.

An intermediate member used for the golf club 500 is the intermediate member 14 as in the above-mentioned golf club 2.

The intermediate member 14 is not fixed as in the above-mentioned golf club 2. As in the golf club 2, the intermediate member 14 moves in a predetermined axial range, and does not drop.

An engaging member used for the golf club 500 is the engaging member 20 as in the above-mentioned golf club 2.

The screw 506 used for the golf club 500 is similar to the above-mentioned screw 206. The screw 506 also has a head part and an axial part. The axial part of the screw 506 has a first screw part 510, a second screw part 512, a first non-screw part 514, and a second non-screw part 516. The first screw part 510 is a male screw. The second screw part 512 is a male screw. The first non-screw part 514 is located between the first screw part 510 and the second screw part 512. The second screw part 512 is located on a head part side with respect to the first screw part 510. The second non-screw part 516 is located between the head part and the second screw part 512.

The head body 509 has a screw hole 520. The screw hole 520 is formed in the inner peripheral surface of a flange 522. The screw hole 520 is a body screw part.

The first screw part 510 is a multiple-thread screw. The first screw part 510 is a double-thread screw. The first screw part 510 is a double-thread screw corresponding to a screw hole 34 of the sleeve 8.

The second screw part 512 is a multiple-thread screw. The second screw part 512 is a double-thread screw. The second screw part 512 is a double-thread screw corresponding to the screw hole 520.

A pitch Pt of the second screw part 512 is the same as a pitch Pt of the first screw part 510. A lead Ld of the second screw part 512 is the same as a lead Ld of the first screw part 510.

The outer diameter of the second screw part 512 is greater than the outer diameter of the first screw part 510. The diameter of a valley of the second screw part 512 is greater than the diameter of a valley of the first screw part 510.

As shown in FIG. 22, in the connected state, screw connection between the first screw part 510 and the screw hole 34 is achieved, and screw connection between the second screw part 512 and the screw hole 520 is achieved. In the connected state, the axial position of a screw hole 56 of the intermediate member 14 corresponds to the first non-screw part 514. In the connected state, the screw hole 56 is not screw-connected. This point is the same as the above-mentioned golf club 2 (see FIG. 3).

Each of the embodiments has the following function effects, for example.

[Golf Club 2 of First Embodiment (see FIG. 3)]

(Effect a) The time required for fastening the screw connection is shortened by the multiple-thread screw. Therefore, the shaft 6 is swiftly attached and detached, which improves convenience. (Effect b) The withdrawal of the screw 10 in the disconnected state can be prevented by the intermediate member 14. (Effect c) Engagement between the screw hole 56 and the screw part 62 is facilitated by the intermediate member 14 which is not fixed. (Effect d) The intermediate member 14 is a separate body from the head body 18, and thereby a freedom degree of a processing method of the intermediate member 14 is improved. For this reason, the intermediate member 14 can be processed with high dimensional accuracy. (Effect e) The engaging member 20 is a separate body from the head body 18, and thereby a freedom degree of a processing method of the engaging member 20 is improved. For this reason, the engaging member 20 can be processed with high dimensional accuracy. (Effect f) A position and posture of the intermediate member 14 in the connected state are stabilized with high accuracy by a combination of the highly accurate engaging member 20 and the highly accurate intermediate member 14. (Effect g) Looseness of the screw 10 is prevented by the spring washer 16.

[Golf Club 100 of Second Embodiment (see FIG. 15)]

(Effect a) The time required for fastening the screw connection is shortened by the multiple-thread screw. Therefore, swiftness for attaching and detaching the shaft 6 is increased, which improves convenience. (Effect b) The withdrawal of the screw 10 in the disconnected state can be prevented by the screw hole 110. (Effect e) The engaging member 20 is a separate body from the head body 18, and thereby a freedom degree of a processing method of the engaging member 20 is improved. For this reason, the engaging member 20 can be processed with high dimensional accuracy. (Effect g) Looseness of the screw 10 is prevented by the spring washer 16. (Effect h) Although not illustrated in FIG. 15, in the connected state, the flange 108 is deformed by the axial force acting on the screw. That is, the flange 108 (the vicinity of the screw hole 110) is pulled to the upper side by the axial force, and slightly deformed. The deformation is elastic deformation. Looseness of the screw 10 is less likely to be caused because of the restoring force of the elastic deformation. (Effect i) The looseness of the screw 10 is effectively suppressed by synergy between the effect g and the effect h. (Effect J) Since each of the two screw parts (screw hole 34 and screw hole 110) is the multiple-thread screw, the effect a is further improved.

[Golf Club 200 of Third Embodiment (see FIG. 18)]

(Effect a) The time required for fastening the screw connection is shortened by the multiple-thread screw. Therefore, the shaft 6 is swiftly attached and detached, which improves convenience. (Effect b) The withdrawal of the screw 206 in the disconnected state can be prevented by the screw hole 214. (Effect e) The engaging member 20 is a separate body from the head body 18, and thereby a freedom degree of a processing method of the engaging member 20 is improved. For this reason, the engaging member 20 can be processed with high dimensional accuracy. (Effect g) Looseness of the screw 206 is prevented by the spring washer 208. (Effect h) Although not illustrated in FIG. 18, in the connected state, the flange 212 is deformed by the axial force acting on the screw. That is, the flange 212 (the vicinity of the screw hole 214) is pulled to the upper side by the axial force, and slightly deformed. The deformation is elastic deformation. Looseness of the screw 206 is less likely to be caused because of the restoring force of the elastic deformation. (Effect i) The looseness of the screw 206 is effectively suppressed by synergy between the effect g and the effect h. (Effect J) Since each of the two screw parts (screw hole 34 and screw hole 214) is the multiple-thread screw, the effect a is further improved.

[Golf Club 300 of Fourth Embodiment (see FIG. 20)]

(Effect a) The time required for fastening the screw connection is shortened by the multiple-thread screw. Therefore, the shaft 6 is swiftly attached and detached, which improves convenience. (Effect b) The withdrawal of the screw 206 in the disconnected state can be prevented by the screw hole 214. (Effect g) Looseness of the screw 206 is prevented by the spring washer 208. (Effect h) Although not illustrated in FIG. 20, in the connected state, the flange 212 is deformed by the axial force acting on the screw. That is, the flange 212 (the vicinity of the screw hole 214) is pulled to the upper side by the axial force, and slightly deformed. The deformation is elastic deformation. Looseness of the screw 206 is less likely to be caused because of the restoring force of the elastic deformation. (Effect i) The looseness of the screw 206 is effectively suppressed by synergy between the effect g and the effect h. (Effect J) Since each of the two screw parts (screw hole 34 and screw hole 214) is the multiple-thread screw, the effect a is further improved.

[Golf Club 400 of Fifth Embodiment (see FIG. 21)]

(Effect a) The time required for fastening the screw connection is shortened by the multiple-thread screw. Therefore, the shaft 6 is swiftly attached and detached, which improves convenience. (Effect b) The withdrawal of the screw 506 in the disconnected state can be prevented by the intermediate member 14. (Effect d) The intermediate member 14 is a separate body from the head body 509, and thereby a freedom degree of a processing method of the intermediate member 14 is improved. For this reason, the intermediate member 14 can be processed with high dimensional accuracy. (Effect e) The engaging member 20 is a separate body from the head body 509, and thereby a freedom degree of a processing method of the engaging member 20 is improved. For this reason, the engaging member 20 can be processed with high dimensional accuracy. (Effect f) A position and posture of the intermediate member 14 in the connected state are stabilized with high accuracy by a combination of the highly accurate engaging member 20 and the highly accurate intermediate member 14. (Effect g) Looseness of the screw 206 is prevented by the spring washer 208. (Effect J) Since each of the two screw parts (screw hole 34 and screw hole 56) is the multiple-thread screw, the effect a is further improved.

[Golf Club 500 of Sixth Embodiment (see FIG. 22)]

(Effect a) The time required for fastening the screw connection is shortened by the multiple-thread screw. Therefore, the shaft 6 is swiftly attached and detached, which improves convenience. (Effect b) The withdrawal of the screw 506 in the disconnected state can be prevented by the intermediate member 14. (Effect c) Engagement between the screw hole 56 and the first screw part 510 is facilitated by the intermediate member 14 which is not fixed. (Effect d) The intermediate member 14 is a separate body from the head body 509, and thereby a freedom degree of a processing method of the intermediate member 14 is improved. For this reason, the intermediate member 14 can be processed with high dimensional accuracy. (Effect e) The engaging member 20 is a separate body from the head body 509, and thereby a freedom degree of a processing method of the engaging member 20 is improved. For this reason, the engaging member 20 can be processed with high dimensional accuracy. (Effect f) A position and posture of the intermediate member 14 in the connected state are stabilized with high accuracy by a combination of the highly accurate engaging member 20 and the highly accurate intermediate member 14. (Effect g) Looseness of the screw 506 is prevented by the spring washer 508. (Effect h) Although not illustrated in FIG. 22, in the connected state, the flange 522 is deformed by the axial force acting on the screw. That is, the flange 522 (the vicinity of the screw hole 520) is pulled to the upper side by the axial force, and slightly deformed. Looseness of the screw 506 is less likely to be caused because of the restoring force of the elastic deformation. (Effect i) The looseness of the screw 506 is effectively suppressed by synergy between the effect g and the effect h. (Effect J) Since each of the three screw parts (screw hole 34, screw hole 56, and screw hole 520) is the multiple-thread screw, the effect a is further improved.

The multiple-thread screw is apt to be loosened as compared with the single-thread screw. The effect g, the effect h, and the effect i effectively decrease the easiness of the looseness of the multiple-thread screw.

In the effect h, the deformation amount of the head body (or intermediate member) based on the axial force is preferably equal to or greater than 0.01 mm, and more preferably equal to or greater than 0.03 mm. The deformation amount is measured at a position having the maximum displacement. The deformation amount is increased to some extent, and thereby the restoring force is increased, which can effectively suppress the looseness of the screw. When the deformation amount is excessive, cracks may occur in the head body. In this respect, the deformation amount is preferably equal to or less than 0.08 mm. The deformation amount is adjusted by adjusting the thickness and width of the flange, for example. The deformation amount can be adjusted by changing the material of the flange.

It is possible to make the material of the intermediate member 14 different from the material of the head body 406. Therefore, for example, the intermediate member 14 can also be made of a material having moderate elastic deformability in the golf club 400. In this case, for example, the Young's modulus of the intermediate member 14 can be made lower than the Young's modulus of the head body 406. In this case, a moderate restoring force is obtained, and the looseness of the multiple-thread screw can be effectively suppressed. In respect of strength, the material of the intermediate member 14 is preferably a metal and a resin, and more preferably a metal.

In the golf club 200, the golf club 300, the golf club 400, and the golf club 500, the assembly 12 is fixed in the axial direction by the first screw connection and the second screw connection. For example, in the golf club 200 of the third embodiment (see FIG. 18), the first screw connection is connection between the screw hole 34 and the first screw part 224, and the second screw connection is connection between the screw hole 214 and the second screw part 226. The diameter of the second screw connection is greater than the diameter of the first screw connection. The great diameter increases a rotation moment. Therefore, the second screw connection having a greater diameter effectively suppresses the looseness of the screw 206.

INDUSTRIAL APPLICABILITY

The present invention described above can be applied to all golf club heads.

REFERENCE SIGNS LIST

-   -   2, 100, 200, 300, 400, 500 Golf club     -   4, 104, 204, 304, 404, 504 head     -   6 Shaft     -   8 Sleeve     -   10, 206, 506 Screw (screw for fixing shaft)     -   12 Shaft-sleeve assembly     -   14 Intermediate member     -   16, 208, 508 Washer     -   18, 106, 210, 306, 406, 509 Head body     -   20 Engaging member     -   22 Hosel hole     -   32 Shaft hole     -   34 Screw hole (sleeve screw part)     -   44 Rotation-preventing part of sleeve     -   48 Screw part of engaging member (screw part B)     -   51 Rotation-preventing part of engaging member     -   56 Inner peripheral surface of intermediate member (screw part)     -   70 Screw part of head body (screw part A)     -   72 Hosel external surface located in head     -   110, 214, 520 Body screw part (screw part which can be connected         to screw for fixing shaft) 

1. A golf club comprising: a head; a shaft; a sleeve; and a screw, wherein the sleeve is fixed to a tip part of the shaft; the head has a head body and an engaging member; the engaging member is fixed to the head body; rotation of the sleeve to the head is regulated based on engagement between the sleeve and the engaging member; the sleeve has a sleeve screw part; withdrawal of the sleeve from the head is regulated based on connection between the sleeve screw part and the screw; a connected state where the screw is connected to the sleeve and a disconnected state where the screw is removed from the sleeve can be mutually shifted; and the screw is a multiple-thread screw.
 2. The golf club according to claim 1, wherein the multiple-thread screw is a double-thread screw.
 3. The golf club according to claim 1, wherein the head body has a screw part A for connecting the engaging member; the engaging member has a screw part B; and the screw part A is connected to the screw part B.
 4. The golf club according to claim 1, further comprising an intermediate member, wherein the intermediate member has a screw part which can be connected to the screw; and the screw part of the intermediate member is a multiple-thread screw.
 5. The golf club according to claim 1, wherein the screw has a first screw part, and a second screw part having an outer diameter greater than the first screw part; the head body has a body screw part; in the connected state, the first screw part is connected to the sleeve screw part, and the second screw part is connected to the body screw part; the first screw part and the second screw part are multiple-thread screws; and the sleeve screw part and the body screw part are multiple-thread screws.
 6. The golf club according to claim 5, wherein the head body connected to the second screw part is elastically deformed by an axial force of the screw.
 7. The golf club according to claim 4, wherein a material of the intermediate member is different from a material of the head body.
 8. The golf club according to claim 7, wherein a Young's modulus of the intermediate member is lower than a Young's modulus of the head body. 